Continuous glucose monitor (CGM) sensors that utilize hydrogen peroxide (H2O2) detection may suffer from problems with glucose detection accuracy. The voltage that is needed to oxidize H2O2 is around 600-700 mV vs Ag/AgCl. At this voltage, some common endogenous and exogenous substances such as ascorbic acid, uric acid, and acetaminophen can be easily oxidized. As a result, a false positive bias is often observed if there is an oxidizing interference substance present.
Research has been conducted to identify an interference barrier that can exclude these oxidizing substances by preventing them from reaching the surface of the electrode where oxidation takes place. A common practice is to apply a polymer film/membrane, which is usually negatively charged, onto the sensor so that the interfering substances (most are negatively charged) will be excluded from the reaction center due to repulsive interaction.